Summary:

Researchers are looking to the geologic past to make future projections about climate change. Their research focuses on the ancient Tethys Ocean (site of the present-day Mediterranean Sea) and provides a benchmark for present and future climate and ocean models.

Source: Science Daily

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Abstract.

"The degree to which ocean deoxygenation will alter the function of marine communities remains unclear but may be best constrained by detailed study of intervals of rapid warming in the geologic past. The Paleocene–Eocene Thermal Maximum (PETM) was an interval of rapid warming that was the result of increasing contents of greenhouse gases in the atmosphere that had wide ranging effects on ecosystems globally. Here, we present stable nitrogen isotope data from the Eastern Peri-Tethys Ocean that record a significant transition in the nitrogen cycle.  [...]"

Source: Nature Communications
Authors: Christopher K. Junium, Alexander J. Dickson & Benjamin T. Uveges 
DOI: 10.1038/s41467-018-05486-w

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Abstract.

"Anaerobic ammonium oxidation (anammox) contributes substantially to ocean nitrogen loss, particularly in anoxic marine zones (AMZs). Ammonium is scarce in AMZs, raising the hypothesis that organic nitrogen compounds may be ammonium sources for anammox. Biochemical measurements suggest that the organic compounds urea and cyanate can support anammox in AMZs. [...]"

Source: The ISME Journal
Authors: Sangita Ganesh et al.
DOI: 10.1038/s41396-018-0223-9

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Abstract.

"The late Ediacaran to early Cambrian interval witnessed extraordinary radiations of metazoan life. The role of the physical environment in this biological revolution, such as changes to oxygen levels and nutrient availability, has been the focus of longstanding debate. Seemingly contradictory data from geochemical redox proxies help to fuel this controversy. As an essential nutrient, nitrogen can help to resolve this impasse by establishing linkages between nutrient supply, ocean redox, and biological changes. [...]"

Source: Nature Communications
Authors: Dan Wang et al.
DOI: 10.1038/s41467-018-04980-5

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"Tremendous – and deserved - attention has been paid for the last few years to the scourge of ocean plastics pollution, which we now know reaches the farthest depths of the ocean and can have impacts on ocean life from the smallest plankton to the largest whales.  We know (Jambeck et al., 2015) that some 4.8 million to 12.7 million metric tonnes of plastic enter the ocean each year. UN Environment has estimated the socio-economic costs of ocean plastics pollution at about US$13 billion per year.  We are only beginning to explore and understand the potential human health impacts of plastics in the oceanic food chain. [...]"

Source: United Nations Development Programme
Author: Andrew Hudson

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Abstract.

"Specialized prokaryotes performing biological dinitrogen (N₂) fixation (“diazotrophs”) provide an important source of fixed nitrogen in oligotrophic marine ecosystems such as tropical and subtropical oceans. In these waters, cyanobacterial photosynthetic diazotrophs are well known to be abundant and active, yet the role and contribution of non-cyanobacterial diazotrophs are currently unclear. The latter are not photosynthetic (here called “heterotrophic”) and hence require external sources of organic matter to sustain N₂ fixation.  [...]"

Source: Frontiers in Marine Science
Authors: Mar Benavides et al.
DOI: 10.3389/fmars.2018.00089

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"Nitrogen is essential to marine life and cycles throughout the ocean in a delicately balanced system. Living organisms--especially marine plants called phytoplankton--require nitrogen in processes such as photosynthesis. In turn, phytoplankton growth takes up carbon dioxide from the atmosphere and helps regulate global climate. [...]"

Source: EruekAlert

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quantifying the effects of nutrient utilization versus denitrification over the past 600 years

Abstract. 

"The sedimentary stable nitrogen isotope compositions of bulk organic matter (δ¹⁵N_bulk) and silicon isotope composition of diatoms (δ³⁰Si_BSi) both mainly reflect the degree of past nutrient utilization by primary producers. However, in ocean areas where anoxic and suboxic conditions prevail, the δ¹⁵N_bulk signal ultimately recorded within the sediments is also influenced by water column denitrification causing an increase in the subsurface δ¹⁵N signature of dissolved nitrate (δ¹⁵NO₃⁻) upwelled to the surface. [...]"

Source: Biogeosciences
Authors: Kristin Doering et al.
DOI: 10.5194/bg-2018-118

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Abstract.

"In estuarine and coastal ecosystems, the majority of previous studies have considered coupled nitrification-denitrification (CND) processes to be exclusively sediment based, with little focus on suspended particulate matter (SPM) in the water column. Here, we present evidence of CND processes in the water column of Hangzhou Bay, one of the largest macrotidal embayments in the world. [...]"

Source: Scientific Reports
Authors: Weijing Zhu et al.
DOI: 10.1038/s41598-018-20688-4

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Abstract.

"Nitrogen is an essential component of all living organisms and the main nutrient limiting life on our planet. By far, the largest inventory of freely accessible nitrogen is atmospheric dinitrogen, but most organisms rely on more bioavailable forms of nitrogen, such as ammonium and nitrate, for growth. [...]"

Source: Nature Reviews Microbiology
Authors: Marcel M. M. Kuypers, Hannah K. Marchant & Boran Kartal
DOI: 10.1038/nrmicro.2018.9

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